Swarm. The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny fiend. The swarm can't regain hit points or gain temporary hit points.

New Shell. The swarm can enter the body of a medium humanoid that has been dead for less than one week, and turn it into a new Apollyon after 1 day.

Hivemind. Effects that apply confusion or frightened affect the whole swarm, no matter how spread apart the swarm is.

Innate Spellcasting The Apollyon Swarm's innate spellcasting ability is Wisdom (Spell Save 13). The Apollyon Swarm can cast the following spells without any material components.

ACTIONS

The Apollyon Swarm is rarely seen on its own. It is a swarm of fiendish insects that are governed by a single mind. The Apollyon Swarm does not like to be left exposed for long, and will quickly try to find a corpse to construct a new Apollyon with.